Inserting the head. The degree of insertion of the fetal head into the pelvis. Determination of the degree of insertion of the fetal head. What you need to know if the fetus is in low cephalic presentation
Extensor presentation of the fetal head is an obstetric situation in which the fetal head in the first stage of labor is firmly established in one degree or another of extension.
ICD-10 CODE
O32.3 Facial, frontal or chin presentation of the fetus requiring maternal medical attention.
EPIDEMIOLOGY
The incidence of extensor presentation of the head is 0.5–1% of cases of all births.
CLASSIFICATION
According to the degree of extension of the head, the following variants of extension presentation are distinguished:
anterior cephalic presentation;
frontal presentation;
·facial presentation (Fig. 52-1).
Rice. 52-1. Extensor presentation of the fetal head.
A - anterior cephalic; B - frontal; B - facial.
ETIOLOGY
Reasons for the development of extension presentations:
decreased tone and uncoordinated contractions of the uterus;
·narrow pelvis (especially flat);
decreased tone of the pelvic floor muscles;
small or excessively large size of the fetus;
decreased tone of the muscles of the anterior abdominal wall;
·lateral displacement of the uterus;
fetal thyroid tumor;
·stiffness of the atlanto-occipital joint of the fetus;
shortness of the umbilical cord.
CLINICAL PICTURE AND DIAGNOSTICS
ANTEROCEPTICAL PRESENTATION
Recognition of anterior cephalic presentation is based on vaginal examination data: you can simultaneously palpate the large and small fontanels of the head, which are located at the same level, or the large fontanelle below the small one. The sagittal suture at the entrance to the pelvis is usually transverse, sometimes slightly oblique.
The type (anterior, posterior) is determined by the relationship of the back of the fetus to the anterior abdominal wall.
Diagnosis of anterior cephalic presentation is based on the following differences from the posterior view of occipital presentation:
· with an anterior cephalic presentation, you can palpate the large and small fontanel, often the large fontanel is lower than the small one, and with a posterior view of the occipital insertion, only the small fontanel, sometimes the posterior angle of the large fontanel, can be felt;
· in case of anterior cephalic presentation, the fixation points during eruption of the head are the glabella and the occipital protuberance; in the case of a posterior view of the occipital insertion, the anterior edge of the scalp and the area of the suboccipital fossa;
· the birth tumor is located in the area of the large fontanel (tower head).
FRONTAL PRESENTATION
Frontal presentation is transitional from anterior cephalic to facial. Very rarely (in 0.021% of cases), having descended to the pelvic floor, the head erupts in the frontal insertion.
Diagnosis of frontal presentation is based on data from auscultation, external and vaginal examination.
The fetal heartbeat can be heard from the thoracic surface of the fetus. During external examination, the sharp protrusion of the chin is felt on one side, and the angle between the back of the fetus and the back of the head is felt on the other; These data give rise to the assumption of frontal presentation. A reliable diagnosis can only be made with ultrasound and vaginal examination. At the same time, the frontal suture, the anterior edge of the large fontanel, superciliary arches, orbits, and bridge of the nose are determined; the mouth and chin cannot be felt.
FACIAL PRESENTATION
Facial presentation is a fairly common variant of extensor cephalic presentation of the fetus, an extreme degree of extension of the head.
There are primary and secondary facial presentation. The first occurs before the onset of labor due to a tumor of the fetal thyroid gland and is observed very rarely; secondary facial presentation occurs more often, for example, with a flat pelvis. Usually, at first, a frontal presentation occurs at the entrance to the pelvis, which, as the head descends and extends, turns into a facial presentation.
The wire point is the chin. Most authors determine the type of fetus by the location of the back, some authors determine the type of fetus by the chin.
Diagnosis of facial presentation is based on data from external palpation, auscultation and vaginal examination. During an external examination, a protruding chin is identified on one side above the entrance to the pelvis, and on the other - a depression between the back of the head and the back. The fetal heartbeat is better heard from the chest rather than from the fetal back. The most convincing data are from a vaginal examination, in which you can determine the chin, nose, brow ridges, and frontal suture. If there is significant swelling of the face, there is a risk of an erroneous diagnosis of breech presentation.
Differential diagnosis is based on determining the position of bone formations. In a facial presentation, you can feel the chin, brow ridges, and the upper part of the orbit. In case of breech presentation, the coccyx, sacrum, and ischial tuberosities are palpated. The examination should be carried out very carefully so as not to damage the eyeball, mucous membrane of the mouth, and external genitalia; insertion of an examining finger into the fetal mouth is undesirable, since this is associated with the danger of a premature reflex onset of respiratory movements.
EXAMPLES OF FORMULATION OF DIAGNOSIS
·First stage of term labor. Anterocephalic presentation. Early rupture of amniotic fluid.
·Second stage of term labor. Facial presentation of the fetal head. Threat of perineal rupture.
MECHANISM OF BIRTH
MECHANISM OF LABOR IN ANTEROCAPITAL PRESENTATION
The mechanism of labor in cephalic presentation consists of five elements. The first moment of labor - instead of flexion of the head, slight extension occurs. The second point is that as the head descends into the pelvic cavity, an internal rotation occurs, with a large fontanelle facing anteriorly. On the pelvic floor, the sagittal suture is straight, the forehead is facing the symphysis, the back of the head is facing the coccyx. The third point is bending. The cutting of the head occurs in such a way that the first to emerge from the genital fissure is the area of the greater fontanelle and the neighboring areas of the parietal bones. After the frontal tubercles emerge from under the pubic arch, the head is fixed in the region of the glabella at the lower edge of the pubic arch (Fig. 52-2) and flexed, and the parietal tubercles are born above the perineum.
The fourth moment - the head extends, fixing the back of the head in the perineum area, the face and chin are released from under the pubis (Fig. 52-3). The fifth moment - internal rotation of the shoulders, external rotation of the head and birth of the fetal body - occurs in the same way as with occipital presentation (Table 52-1).
Rice. 52-2. Eruption of the head with anterior cephalic presentation. The first point of fixation is the area of the bridge of the nose; flexion of the head.
Rice. 52-3. Extension of the head in anterocephalic presentation.
The wire point for anterocephalic presentation is the large fontanelle. When the head erupts, two points of fixation appear: the region of the glabella and the occipital protuberance. A circle corresponding to the direct size of the fetal head is cut through the vulvar ring.
Table 52-1. The mechanism of labor in extensor presentations
| Criteria | Anterocephalic | Frontal | Facial |
| 1st moment | Moderate extension of the head | Strong extension of the head | Maximum head extension |
| 2nd moment | Internal rotation of the head during the transition from the wide part of the pelvis to the narrow part with the formation of a posterior view | Internal rotation of the head during the transition from the wide part of the pelvis to the narrow one | Internal rotation of the head to form a rear view |
| 3rd moment | Head flexion | Head flexion | Head flexion |
| 4th moment | Head extension | Head extension | |
| 5th moment | Internal rotation of the shoulders and external rotation of the head | Internal rotation of the shoulders and external rotation of the head | |
| Wire point | Great fontanelle | Forehead | Chin |
| Fixation point | The bridge of the nose is the lower inner edge of the pubic symphysis; |
The upper jaw is the lower inner edge of the symphysis pubis, occipital protuberance - tip of coccyx |
Hyoid bone - lower inner edge of the pubic symphysis |
| The size at which the head is born | Straight - 12 cm | Upper jaw + occipital protuberance - 12.5–13 cm | Vertical - 9.5 cm |
| Birth tumor | In the area of the large fontanel | In the forehead area | In the chin area |
| Head shape | Tower | Triangular | Non-standard |
MECHANISM OF LABOR IN FRONTAL PRESENTATION
The mechanism of labor in frontal presentation consists of the following stages. At the first moment, at the entrance to the pelvis, the head, located with the frontal suture in a transverse or slightly oblique dimension, expands. At the second moment of labor, having descended to the bottom of the pelvis, the head turns with the face anterior, the back of the head posterior (posterior view). When cutting into the genital fissure, the forehead, the root of the nose and part of the crown of the head are shown (Fig. 52-4). Next, two points of fixation appear sequentially: first, under the pubic arch, the area of the upper jaw, the head is slightly bent, the birth of the occiput occurs (the third moment of the birth mechanism), then the occiput area is fixed above the perineum, a slight extension of the head occurs and the birth of the lower part of the face and chin occurs (the fourth moment of the birth mechanism ).
Internal rotation of the shoulders and external rotation of the head (the fifth moment of the birth mechanism) occur in the same way as with occipital presentation.
Rice. 52-4. Head cutting in frontal presentation.
The wire point for frontal presentation is the forehead; When the head erupts, two points of fixation appear: the upper jaw and the occipital protuberance. The head in frontal presentation passes through the plane of the pelvis with a large oblique size and is formed by a circle that passes through the upper jaw and parietal tubercles. A birth tumor forms on the forehead.
MECHANISM OF BIRTH IN FACIAL PRESENTATION
The mechanism of labor in facial presentation includes the following points. At the entrance to the pelvis, extension of the head occurs (the first moment of the birth mechanism). The facial line (running from the frontal suture along the back of the nose to the chin) stands at the entrance to the pelvis in a transverse or slightly oblique dimension. Descending into the pelvic cavity (the second moment of the labor mechanism), the head makes an internal rotation; on the pelvic floor, the head turns anteriorly with the chin (the third moment of the labor mechanism, Fig. 52-5). The first thing to appear from the genital slit is a swollen mouth with bluish, thick lips. The area of the hyoid bone is fixed under the pubis (Fig. 52-6), with strong stretching of the perineum, the forehead, crown and back of the head erupt (the fourth moment of the birth mechanism); those. the head bends. The circle through which the head erupts corresponds to the vertical dimension (from the crown of the hyoid bone). Internal rotation of the shoulders and external rotation of the head (the fifth moment of the birth mechanism) occur in the same way as with occipital presentation. Severe swelling of the cheek (more on one side), nose, lips, and sometimes bruising are noted (Fig. 52-7). In the first days, a newborn lies with his head extended.
Rice. 52-5. Facial presentation, internal rotation of the head with the chin anterior (occurs on the pelvic floor).
Rice. 52-6. Facial presentation, face cutting.
Rice. 52-7. Configuration of the head in facial presentation.
TACTICS OF CHILDREN
The course of labor with anterior cephalic presentation has the following features: the second period is delayed, which entails the danger of hypoxia and injury to the fetus; eruption of the head occurs in a circle corresponding to the direct size of the head, which often leads to excessive stretching and tearing of the perineum.
With an anterocephalic presentation of the fetus, expectant management of labor is possible, but this condition is considered a relative indication for CS surgery. If signs of deterioration in fetal oxygenation are detected, hypoxia is treated, and if there are conditions and indications for delivery, obstetric forceps are applied (this operation is performed by a highly qualified doctor). When performing traction, it is necessary to strictly follow the mechanism of labor.
With frontal presentation, labor takes a long time, and very often injuries occur in the mother (genitourinary fistula, perineal rupture, uterine rupture) and fetus (intracranial injury). Due to the danger of these complications, frontal presentation is an absolute indication for operative delivery (CS). In case of intrauterine fetal death, a fetal destruction operation (craniotomy) is performed.
With a facial presentation, the average duration of labor is one and a half times longer than with an occipital presentation; the frequency of cases of untimely discharge of water increased by 2 times. In this regard, the risk of birth injuries and fetal hypoxia, stillbirth, and chorioamnionitis is high. Childbirth with anterior facial presentation is impossible, since the sharply extended head cannot pass through the pelvis. Childbirth with anterior facial presentation is usually managed conservatively; in 90–95% of cases, childbirth occurs on its own. At the beginning of labor, the woman in labor should be placed on the side toward which the fetus's chin is facing. In the anterior type of facial presentation, if the head is not fixed at the entrance to the pelvis, a CS is performed; if the head has dropped into the pelvic cavity and the fetus has died, a fetal destruction operation (craniotomy) is indicated.
At the beginning of normal labor, the head is installed above the entrance to the pelvis or inserted into the entrance in such a way that the sagittal suture, coinciding with the wire line of the pelvis, is located at the entrance at the same distance from the womb and promontory, which facilitates its passage through the birth canal. In most cases, the head is inserted into the entrance in such a way that the anterior parietal bone is deeper than the posterior one (the sagittal suture is closer to the promontory) - asynclitic insertion. Weak and moderately expressed anterior asynclitism favors the passage of the head through the birth canal, which is not spacious enough for it.
Sometimes asynclitism is so pronounced that it prevents further advancement of the head along the birth canal - pathological asynclitism.
Distinguish two types of asynclitism:
A) anterior (Nägele asynclitism)- the sagittal suture is close to the sacrum, and the anterior parietal bone descends first into the plane of the inlet of the small pelvis, the leading point is located on it
b) posterior (Litzmann asynclitism)- the posterior parietal bone descends first into the pelvis, the sagittal suture is deflected anteriorly towards the womb
Reasons: relaxed state of the abdominal wall, relaxed state of the lower segment of the uterus, the size of the fetal head and the state of the pelvis of the woman in labor (its narrowing and especially flattening - a flat pelvis, as well as the degree of pelvic inclination).
Diagnostics: the sagittal suture is deflected from the axis of the pelvis towards the symphysis or sacrum and stably maintains this position.
Childbirth forecast with anterior asynclitism favorable in the case of a mild discrepancy between the sizes of the mother’s pelvis and the fetal head. The head undergoes a strong configuration, acquiring an oblique shape with indentation phenomena in the bones of the skull. Under the influence of strong labor, the presenting parietal bone penetrates deeper and deeper into the pelvis and only after that the other parietal bone, which lingers at the cape, descends.
Posterior asynclitism more often it is a consequence of childbirth with a generally narrowed flat and flat-rachitic pelvis. The posterior parietal bone is inserted first in transverse size. With lateral flexion of the fetal head, the sagittal suture deviates towards the symphysis. The head is inserted in a state of slight extension.
A pronounced degree of anterior and especially posterior asynclitism is indication for caesarean section.
Incorrect position of the head (deviations from the normal biomechanism of labor in occipital presentations)
1. High straight position of the swept seam - condition, the fetus at the beginning of labor faces its back directly anteriorly (anterior view) or posteriorly (posterior view), and its head stands with an arrow-shaped suture above the straight size of the entrance to the pelvis.
Etiology: violation of the relationship between the head and pelvis (narrow pelvis, wide pelvis), prematurity of the fetus (small size of its head), changes in the shape of its head (wide flat skull) and the shape of the pelvis (round shape of the pelvic inlet with its transverse narrowing).
Childbirth is possible under certain conditions: the fetus should not be large, its head should be well shaped, the mother’s pelvis should be of normal size, labor should be of sufficient force. The fetal head moves along the birth canal in the direct size of all planes of the small pelvis, without making an internal rotation. Labor is protracted.
Complications: weakness of labor, difficulty in advancing the head, compression of the soft tissues of the birth canal, fetal hypoxia, intracranial injury to the fetus.
Delivery: in the anterior view - independent birth; in the posterior case, spontaneous childbirth is rare, most often cesarean section, obstetric forceps, craniotomy.
2. Low transverse position of the swept seam - pathology of childbirth, characterized by the position of the head with a sagittal suture in the transverse dimension of the pelvic outlet, in which internal rotation of the head does not occur.
Etiology: narrowing of the pelvis (flat pelvis, especially flat rachitic), small size of the fetal head, decreased tone of the pelvic floor muscles.
Complications: compression and necrosis of the soft tissues of the birth canal and bladder, ascending infection, uterine rupture, fetal hypoxia.
Delivery: with active labor, labor ends spontaneously, otherwise they resort to cesarean section, application of obstetric forceps, or craniotomy.
Extensor presentation and insertion of the fetal head. Features of the biomechanism of childbirth. Course and management of labor.
Extensor presentation of the fetal head: anterocephalic, frontal, facial.
Happens quite often.
The formation of facial presentation most often occurs during childbirth with a flat pelvis. Usually, a frontal presentation is formed at the entrance to the small pelvis, which, as the head lowers and further extends it, turns into a facial presentation.
The wire point is chin. If the fetus's chin is facing anteriorly, this is the so-called anterior type of facial presentation; if the chin is turned posteriorly - the posterior type of facial presentation.
Biomechanism of childbirth.
First moment- maximum extension of the head above the entrance to the pelvis. The facial line is established in the transverse or slightly oblique size of the entrance to the pelvis.
Second point- internal rotation of the head occurs only on the pelvic floor. The chin turns forward.
Third point- a fixation point is formed between the lower edge of the pubis and the hyoid bone of the fetus. The head bends around this fixation point.
Fourth point- internal rotation of the shoulders and external rotation of the head.
With a facial presentation, the head is erupted in a circle corresponding to the vertical size and equal to (32 cm).
Diagnosis of facial presentation It can only be reliably diagnosed during a vaginal examination, when the chin, nose, brow ridges, and frontal suture are determined. If there is significant swelling of the face, there is a risk of misdiagnosis of breech presentation instead of facial presentation.
The course of labor. Childbirth takes longer, and amniotic fluid often does not drain in a timely manner. The course of labor is especially unfavorable with the so-called posterior type of facial presentation (the chin is turned backward). Spontaneous birth with this type is impossible, because the sharply extended head and shoulders cannot pass through the pelvis. In these cases, childbirth ends with craniotomy.
Anomalies of head insertion.
High straight head position- the sagittal suture is located in the direct dimension of the entrance to the small pelvis. This pathology often occurs with narrow pelvises (transversely narrowed). The course of labor with a high erect head is usually very long; hypoxia, intracranial injury are often observed, and there is a danger of birth injury to the mother.
If the woman's head is positioned high and straight, observation is necessary to promptly identify signs of discrepancy and resolve the issue of performing a cesarean section.
Low transverse position of the head. This term defines the position of the head with a sagittal suture in the transverse dimension of the pelvic cavity (average transverse position of the head) or even at its exit (low or deep transverse position of the head). This pathology often occurs with flat pelvises. Childbirth rarely ends on its own. In the interests of maternal and fetal health, preference should be given to caesarean section.
Asynclitic head insertion. Extra-axial insertion, when the sagittal suture deviates from the median position either towards the promontory (anterior asynclitism) or towards the pubis (posterior asynclitism). Asynclitic insertions occur in narrow pelvises, most often in flat-rachitic ones. With minor degrees of asynclitism, labor ends spontaneously. Severe anterior and posterior asynclitism is a pathological phenomenon and serves as an indication for abdominal delivery.
Test questions and sample answers:
1. Name the three degrees of extension of the head.
1st degree - anterior cephalic presentation;
2nd degree - frontal presentation;
3rd degree - facial presentation.
2. What is the etiology of extension presentations and abnormal insertion of the head?
Standard answer: narrow pelvis, spatial discrepancy between the fetal head and the pelvis, drooping abdomen, pelvic floor insufficiency, excessive fetal mobility, thyroid tumors, neck stiffness.
3. What are the methods for diagnosing extension presentations and abnormal head insertions?
Sample answer:
o) external inspection;
b) listening to the fetal heartbeat;
c) vaginal examination.
4. What are the main points of the biomechanism of labor during cephalic presentation?
Sample answer:
a) slight extension of the head;
c) flexion of the head;
d) extension of the head;
e) internal rotation of the shoulders and external rotation of the head.
5. What serves as a wire point for anterior cephalic presentation?
Ethical answer: large fontanel.
6. What are the points of fixation in anterocephalic presentation?
Sample answer: bridge of the nose, occipital protuberance.
7. What is the circumference of the head during an anterior cephalic presentation?
Standard answer: circumference corresponding to the direct size of the head -34 cm.
8. What are the main points of the biomechanism of labor in frontal presentation?
Sample answer:
a) average degree of extension of the head;
b) internal incorrect rotation of the head;
c) flexion of the head;
d) extension of the head;
e) internal rotation of the shoulders, external rotation of the head.
9. What serves as a wire point for frontal presentation of the head?
Response standard; forehead.
10. What are the points of fixation for frontal presentation of the head?
Sample answer: upper jaw, suboccipital fossa.
11. What is the circumference of the erupting head in frontal presentation?
Sample answer: the circle passing through the upper jaw and the suboccipital fossa is -38-42 cm.
12. What are the main points of the biomechanism of labor during facial presentation?
Sample answer:
a) maximum extension of the head;
6) internal rotation of the head with the back of the head;
c) flexion of the head;
d) internal rotation of the shoulders, external rotation of the head.
13. What serves as the wire point for facial presentation?
Standard answer: chin.
14. What is the fixation point in facial presentation?
Sample answer: hyoid bone.
15. What is the circumference of the erupting head in facial presentation?
Standard answer: the circle corresponding to the vertical size is 32 cm.
16. Which part of the fetus determines the appearance of a facial presentation?
Sample answer: along the chin.
17. What are the distinguishing features of facial and breech presentation?
Standard answer: with a facial presentation, the brow ridges, eye sockets, nose, mouth are determined, with a breech presentation - the coccyx, sacrum, anus.
18. What are the complications during childbirth with an extension presentation?
a) protracted nature of labor;
b) fetal asphyxia;
c) injuries to mother and fetus.
19. What are the measures to prevent complications during childbirth with an extensor presentation of the head?
Sample answer:
a) timely diagnosis of extension presentations;
b) choosing a rational method of delivery.
20. What is the definition of “head insertion”?
Sample answer: the relationship of the sagittal suture to the promontory and the upper edge of the pubis.
21. What types of head inserts do you know? Describe them?
Sample answer:
a) synclitic and asynclitic;
b) synclitic - the location of the swept suture is at an equal distance from the promontory and the womb, or promontory.
c) asynclitic - deviation of the sagittal suture towards the pubis.
22. What is called anterior asynclitism?
Sample answer: deviation of the sagittal suture towards the promontory, leading to insertion of the anterior parietal bone into the pelvic cavity.
23. What is called posterior asynclitism?
Sample answer: deviation of the sagittal suture towards the pubis, leading to insertion of the posterior parietal bone into the pelvic cavity.
24. What are the degrees of posterior asynclinism?
Standard answer: posterior parietal inclination, posterior parietal insertion, posterior auricular insertion.
25. What is the prognosis for the course of labor at various degrees of asynclitic insertion?
Sample answer: With a posterior parietal inclination, childbirth through the birth canal is possible, but with a posterior parietal and posterior auricular insertion, it is impossible.
26. How to understand the high straight position of the head?
Sample answer: the location of the head with a sagittal suture in a straight line is measured at the entrance to the pelvis.
27. What is the medium and low transverse position of a swept seam?
Standard answer? the location of the sister-in-law with a sagittal suture in the transverse dimension of the cavity and the outlet of the small pelvis.
Synclitic (axial) insertion of the head is an insertion in which the sagittal suture is located at the same distance from the pubic symphysis and the sacral promontory, i.e., along the pelvic axis. In the case of asynclitic (extra-axial) insertion, the sagittal suture is deviated closer to the promontory or to the pubic symphysis. If the sagittal suture is closer to the promontory, then the anterior parietal bone is inserted - anterior, or non-Gel, asynclitism is formed (anteroparietal insertion of the head). When the sagittal suture is located closer to the pubic symphysis, the posterior parietal bone is inserted and posterior, or Litzmann, asynclitism is formed (posterior parietal insertion of the head). Anterior parietal asynclitism occurs with narrow, mainly flat pelvises. If it is moderate, then, being adaptive, it favors the passage of the head through the narrowed entrance of the flat pelvis; strong degrees of asynclitic insertion of the head are pathological; they complicate or disrupt childbirth.
Posterior parietal asynclitism always refers to a pathological insertion and not an adaptive one.
The occurrence of asynclitism is facilitated by a narrow pelvis, a flabby abdominal wall (saggy abdomen), prolapse of the arm near the head and other deviations in the biomechanism of childbirth.
The diagnosis of asynclitic insertion is made by vaginal examination. In this case, they are guided by the fact that the sagittal suture is deviated from the axis of the pelvis towards the pubic symphysis or sacrum and stably maintains this position.
Anterior asynclitism (anteroparietal insertion) is characteristic of the biomechanism of childbirth with a simple flat, sometimes with a flat rachitic pelvis. With a flat pelvis, the head, encountering an obstacle from the side of the promontory, is held there by the posterior parietal bone, so the anterior parietal bone is inserted first. In the case of lateral flexion of the head towards the posterior shoulder, the sagittal suture is deviated towards the promontory.
Insertion of the head by the anterior parietal bone in the transverse dimension of the plane of the entrance to the pelvis in a state of slight extension and prolonged standing of the head in the entrance are characteristic features of the biomechanism of labor for flat and planar-rachitic pelvises. The prognosis for childbirth with anterior asynclitism is favorable if there is a mild discrepancy between the mother’s pelvis and the fetal head. However, even in this case, the head undergoes a strong configuration, acquiring an oblique shape with depressions in the bones of the skull. Under the influence of strong labor, the presenting parietal bone penetrates deeper and deeper into the pelvis and only after that the other parietal bone, which lingers at the cape, descends.
Posterior asynclitism occurs more often with generally narrowed flat and planar-rachitic pelvises. The posterior parietal bone is inserted first in transverse size with lateral flexion of the fetal head towards the anterior shoulder; the sagittal suture deviates towards the pubic symphysis. The head is inserted in a state of slight extension. With a sharp degree of posterior asynclitism at the cape, it is possible to determine the fetal ear.
Table of contents of the topic “Fetal articulation (habitus).”:1. Articulation of the fetus (habitus). Fetal position (situs). Longitudinal position. Transverse position. Oblique position.
2. Fetal position (positio). Type of position (visus). First position of the fetus. Second position of the fetus. Front view. Back view.
3. Presentation of the fetus (praesentatio). Head presentation. Breech presentation. Presenting part.
4. External techniques for obstetric examination (Leopold's techniques). Leopold's first move. Purpose and methodology of the study (reception).
5. Second appointment of external obstetric examination. Leopold's second move. Purpose and methodology of the study (reception).
6. Third appointment of external obstetric examination. Leopold's third move. Purpose and methodology of the study (reception).
7. Fourth appointment of external obstetric examination. Leopold's fourth move. Symptom of running. Purpose and methodology of the study (reception).
9. Auscultation of the fetus. Listening to the abdomen of a pregnant woman and woman in labor. Fetal heart sounds. Places of best listening to fetal heart sounds.
10. Determination of gestational age. Time of the first fetal movement. Day of the last menstruation.
Degree of insertion of the fetal head into the pelvis It is recommended to define as follows. During the fourth external examination of the obstetric examination, having penetrated the fingers of both hands as deeply as possible into the pelvis and pressing on the head, they make a sliding movement along it towards themselves.
Rice. 4.21. Occipital presentation. The head is above the entrance to the pelvis (the fingers of both hands can be placed under the head).With a high position of the fetal head when it is movable above the entrance, during external examination it is possible to place the fingers of both hands under it and even move it away from the entrance (Fig. 4.21).
Rice. 4.22. Occipital presentation. The head is at the entrance to the pelvis in a small segment (the fingers of both hands, sliding along the head, diverge in the direction of the arrows).
If the fingers move apart, the head is at the entrance to the pelvis by the small segment m (Fig. 4.22).
Rice. 4.23. Occipital presentation. The head is at the entrance to the small pelvis with a large segment (the fingers of both hands sliding along the head converge in the direction of the arrows).
If the hands sliding along the head converge, then the head or located in a large segment at the entrance, or walked through the entrance and went down into the deeper sections (planes) of the pelvis (Fig. 4.23).
If the fetal head penetrates so deeply into the pelvic cavity that it completely fills it, then usually palpate the head externally no longer possible.
